The GI Surgical Modeling Core provides unique murine surgical services (bariatric and other novel surgical procedures). This core was established to enhance the investigative efforts of the VDDRC investigators and provide avenues of research that otherwise would not be feasible. The primary rational for the core rests in the growing number of mice having genetic alterations with relevance or potential relevance to digestive diseases and the need for surgical and experimental techniques that are necessary to study the impact of genetic (or pharmacologic) manipulations. The procedures require skill and practice in order to study healthy, unstressed mice. The core has skilled surgeons that are capable of adapting a range of procedures to suit specific needs of VDDRC members including bariatric surgical procedures, surgical models for Barrett's esophagus and liver transplantation and ischemia/reperfusion injury models. The quality of the results that are obtained using surgical models is directly related to the general health of the animal. The Core has placed significant emphasis on providing murine models that are free of avoidable, undesired complications. Pre and post-operative care is as important to the success of the procedure as the surgical procedure itself. The overall goal of the core is to provide murine models of bariatric surgery using procedures that are designed to reflect those performed in humans, liver transplantation, and unique customized surgical models adapted to the needs of VDDRC members. To achieve this goal the core: 1. Provides mouse bariatric surgery models with application to basic and translational research. 2. Provides mouse models of Barrett's esophagus and liver and small bowel transplantation. 3. Provides peri-operative care to ensure that animals are healthy and free of undue stress. 4. Trains investigators in specialized surgical procedures. 5. Responds to the needs of VDDRC investigators through development of new procedures. The Core interacts closely with other VDDRC Cores, the Mouse Metabolic Phenotyping Center (MMPC), the Diabetes Research and Training Center, and the Division of Animal Care to ensure and maximize efficient use of resources and personnel and enhance interdisciplinary collaboration.